Mybatis三剑客一在springboot手动使用Mybatis

1、pom.xml中引入依赖【注意根据自己的spring boot版本选择对应的mysql和mybatis版本】

1.  
   <dependency>
2.  
   <groupId>mysql</groupId>
3.  
   <artifactId>mysql-connector-java</artifactId>
4.  
   </dependency>
5.  
    
6.  
   <dependency>
7.  
   <groupId>org.mybatis.spring.boot</groupId>
8.  
   <artifactId>mybatis-spring-boot-starter</artifactId>
9.  
   <version>2.1.0</version>
10.  
    </dependency>

2、resources/application.xml配置

1.  
   spring:
2.  
   datasource:
3.  
   driver-class-name: com.mysql.cj.jdbc.Driver
4.  
   username: root
5.  
   password:
6.  
   url: jdbc:mysql://127.0.0.1:3306/mall?characterEncoding=utf-8&useSSL=false
7.  
   mybatis:
8.  
   configuration:
9.  
   map-underscore-to-camel-case: true
10.  
    mapper-locations: classpath:mappers/*.xml

3、pojo/Category

1.  
   @Data
2.  
   public class Category {
3.  
   private Integer id;
4.  
    
5.  
   private Integer parentId;
6.  
    
7.  
   private String name;
8.  
    
9.  
   private Boolean status;
10.  
     
11.  
    private Integer sortOrder;
12.  
     
13.  
    private Date createTime;
14.  
     
15.  
    private Date updateTime;
16.  
    }

4、dao/CategoryMapper.java

1.  
   @Mapper
2.  
   public interface CategoryMapper {
3.  
   Category queryById(Integer id);
4.  
   }

5、建立同名xml文件

resources/mappers/CategoryMapper.xml

1.  
   <?xml version="1.0" encoding="utf-8" ?>
2.  
   <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
3.  
   <mapper namespace="com.imooc.mall.dao.CategoryMapper">
4.  
   <sql id="Base_Column_List">
5.  
   id, parent_id, name, status, sort_order, create_time, update_time
6.  
   </sql>
7.  
   <select id="queryById" resultType="com.imooc.mall.pojo.Category">
8.  
   select
9.  
   <include refid="Base_Column_List"></include>
10.  
    from mall_category
11.  
    where id = #{id}
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    </select>
13.  
    </mapper>

注意点：

        namespace对应mapper.java地址

        id对应的是mapper中的方法

        resultType对应的是pojo

        Base_Column_List是公共字段提取

6、application.java注入

1.  
   @SpringBootApplication
2.  
   @MapperScan(basePackages = "com.imooc.mall.dao")
3.  
   public class MallApplication {
4.  
    
5.  
   public static void main(String[] args) {
6.  
   SpringApplication.run(MallApplication.class, args);
7.  
   }
8.  
    
9.  
   }

7、使用

1.  
   package com.imooc.mall;
2.  
    
3.  
   import com.imooc.mall.dao.CategoryMapper;
4.  
   import com.imooc.mall.pojo.Category;
5.  
   import org.junit.Test;
6.  
   import org.junit.runner.RunWith;
7.  
   import org.springframework.beans.factory.annotation.Autowired;
8.  
   import org.springframework.boot.test.context.SpringBootTest;
9.  
   import org.springframework.test.context.junit4.SpringRunner;
10.  
     
11.  
    @RunWith(SpringRunner.class)
12.  
    @SpringBootTest
13.  
    public class MallApplicationTests {
14.  
     
15.  
    @Autowired
16.  
    private CategoryMapper categoryMapper;
17.  
     
18.  
    @Test
19.  
    public void contextLoads() {
20.  
     
21.  
    }
22.  
     
23.  
    @Test
24.  
    public void queryByIdTest() {
25.  
     
26.  
    Category category = categoryMapper.queryById(100001);
27.  
    System.out.println(category.toString());
28.  
    }
29.  
     
30.  
    }

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